Heat and energy recovery and regeneration assembly, system and method

ABSTRACT

A heat recovery system including a chamber having a cooling intake, an emissions intake for receiving exhaust gas from a furnace, and a chamber exhaust to discharge emissions from the chamber, a heat recovery exchanger disposed within the chamber for contacting a mixture of cooling gas from the cooling intake and the exhaust gas to effect heat exchange, a fluid circuit in communication with the heat recovery exchanger, a heat extraction exchanger in fluid communication with the heat recovery exchanger through the fluid circuit to effect heat exchange between the heat extraction exchanger and an airstream running therethrough, and a temperature sensor located in a supply plenum of the furnace and having hi and low temperature set points, the controller is configured so that the furnace is repeatedly cycled when the controller registers temperature sensor signals corresponding to the hi and low temperature set points.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation in part of U.S. patent application Ser. No. 14/029,011 filed Sep. 17, 2013 which is a continuation of U.S. patent application Ser. No. 13/753,585 filed Jan. 30, 2013, the disclosures of which are incorporated herein by reference in their entireties.

FIELD

The disclosed embodiment relates generally to the field of air conditioning and heating systems; more particularly, it concerns a system for efficiently combusting fossil fuels for heating a space.

BACKGROUND

The conventional methodology used in utilizing fossil fuels for heating habitable spaces in commercial, industrial and residential buildings or structures is firing the fuel in a controlled heating chamber or heat exchanger. The heat created by the burning fuel is drawn away by air or water flowing around the outside of the heat exchanger. This can be accomplished by blower fans or pumps. The heat is transferred into the surrounding air or water, heating the conditioned space. The waste or emissions from the combustion reaction is allowed to flow outdoors usually utilizing flue piping to a chimney or stack. The efficiency of the furnace or boiler is calculated by the amount of heat which can be extracted from the heat exchanger and utilized to heat the conditioned space and the percentage of heat and by-products permitted to escape through the flue to be vented outside. This rating or efficiency quantification is placed on the furnace or boiler to depict how efficient it will be.

Releasing carbon and heat saturated emissions into the atmosphere contribute to environmental problems, such as global warming. Not only does carbon monoxide and carbon dioxide add to blanketing the release of heat into space, discharging heat through flue gas emissions adds to this issue by heat pollution. Just an average low to medium efficient residential natural gas, LPG or oil furnace can emit about a half million BTU's of heat waste into the atmosphere each day. Commercial and industrial units can discharge hundreds of millions, and occasionally billions, of BTU's per unit per day. In addition, these common and conventional methods of discharging the flue gas into the atmosphere are wasteful and inefficient.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing aspects and other features of the disclosed embodiment are explained in the following description, taken in connection with the accompanying drawings, wherein:

FIG. 1 is a schematic illustration of a heat recovery assembly in accordance with aspects of the disclosed embodiment.

FIG. 1A is a schematic illustration of a portion of a heat recovery assembly in accordance with aspects of the disclosed embodiment.

FIG. 1B is a schematic illustration of a portion of a heat recovery assembly in accordance with aspects of the disclosed embodiment.

FIG. 1C is a schematic illustration of a portion of a heat recovery assembly in accordance with aspects of the disclosed embodiment.

FIG. 1D is a schematic illustration of a portion of a heat recovery assembly in accordance with aspects of the disclosed embodiment.

FIG. 2 is a schematic illustration of a heat recovery assembly in accordance with aspects of the disclosed embodiment.

FIG. 3 is a schematic illustration of the functionality of aspects of the heat recovery assembly of FIGS. 1 and 2.

FIG. 4 is a schematic illustration of a heat exchange process utilized in aspects of the heat recovery assembly of FIGS. 1 and 2.

FIG. 5 is a schematic illustration of a heat recovery system in accordance with aspects of the disclosed embodiment.

FIG. 5A is a schematic illustration of a heat recovery system in accordance with aspects of the disclosed embodiment.

FIG. 6 is a schematic illustration of a heat recovery system utilizing a heat recovery ventilator assembly in accordance with aspects of the disclosed embodiment.

FIG. 7 is a schematic illustration of a wiring diagram in accordance with aspects of the heat recovery system illustrated in FIGS. 5 and 5A.

FIG. 8A is a perspective view of a heat recovery system in accordance with aspects of the disclosed embodiment.

FIG. 8B is a perspective view of a heat recovery system in accordance with aspects of the disclosed embodiment.

FIG. 9 is a perspective view of a heat recovery system in accordance with aspects of the disclosed embodiment.

FIG. 10 is a schematic illustration of a cut-away view in accordance with aspects of the heat recovery system illustrated in FIG. 9.

FIG. 10A is a schematic illustration of a cut-away view in accordance with aspects of the heat recovery system illustrated in FIG. 9.

FIG. 11 is a schematic illustration of a heat recovery system in accordance with aspects of the disclosed embodiment.

FIG. 12 is a schematic illustration of a heat recovery system in accordance with aspects of the disclosed embodiment.

FIG. 13 is a schematic illustration of a heat recovery system in accordance with aspects of the disclosed embodiment.

FIGS. 14A-14F are schematic illustrations of a portion of a heat recovery system in accordance with aspects of the disclosed embodiment.

FIG. 15 is a schematic illustration of a heat recovery system in accordance with aspects of the disclosed embodiment.

FIG. 16 is a schematic illustration of a heat recovery system in accordance with aspects of the disclosed embodiment.

FIG. 17 is a schematic illustration of a portion of a heat recovery system in accordance with aspects of the disclosed embodiment.

FIGS. 18A-18C are a flow diagram for operation of a heat recovery system in accordance with aspects of the disclosed embodiment.

Like reference numerals refer to like parts throughout the several views of the drawings.

DETAILED DESCRIPTION OF THE DISCLOSED EMBODIMENT

As illustrated in the accompanying drawings, the aspects of the disclosed embodiment are directed to a heat and energy recovery assembly and system, in addition to methods of using the same. The heat and energy recovery assembly and system in accordance with aspects of the disclosed embodiment may be adapted for use with any suitable heating unit such as in a furnace of an HVAC system, boiler system or any other system where heat energy from fuel combustion is utilized for heating air spaces or other fluid medium. Although the aspects of the disclosed embodiment will be described with reference to the drawings, it should be understood that the aspects of the disclosed embodiment can be embodied in many forms. In addition, any suitable size, shape or type of elements or materials could be used.

In one aspect of the disclosed embodiment, a heat recovery assembly/system 100 is provided, as illustrated in FIG. 1 which when combined with a heating furnace 2000 in a heat recovery system 200 (see for exemplary purposes only FIGS. 5 and 5A) delivers heat to an area or habitat to be heated such that the heat recovery assembly 100 captures and delivers heat from heated air that is circulated in the habitat, exhaust gas from the furnace 2000 and heat stored in the thermal mass that is the furnace assembly. As may be realized, the furnace 2000 includes a controller 1311F that includes any suitable non-transitory program code for effecting a heating cycle of the furnace 2000. For example, every time a thermostat, such as thermostat TSH, calls for heat, the controller 1311F of the furnace 2000 detects the call for heat (e.g. receives a signal from the thermostat TSH) and starts the furnace heating cycle by first activating the furnace exhaust induction fan motor. Once the controller 1311F confirms proper exhaust pressure is present, the furnace igniter is turned on and verified by the control system. The furnace fuel valve FV opens, the furnace burners FBRN light and heat creation begins. As an example, on a 100,000 btuh furnace, heat is created at a rate of about 28 btus per second. The motor of the furnace blower FIB cannot be turned on until the furnace heat exchanger FHX is hot enough to deliver warm air to a habitat to be heated. For a period (e.g. a latent heating period) of about 1 to about 2 minutes on most furnaces, while the heat exchanger is warming up, there is no air blowing along the outside of the furnace heat exchanger FXH. If the furnace heat exchanger FHX warm up or latent cycle is about 1 minute long, for exemplary purposes only, approximately 1500 btus of fuel is consumed and that energy is either stored in the thermal mass of the furnace heat exchanger FHX or exhausted out of the furnace exhaust 2100. When the motor of the furnace blower FIB is finally turned on heat is transferred from the furnace heat exchanger FHX to, for example the air from the return plenum 1300 (e.g. the source heating period). When the heat call from the thermostat TSH is satisfied, the furnace burners FBRN are turned off however, according to the furnace programming the furnace blower continues to run for about 2 to about 4 minutes delivering additional heat to the house (e.g. the residual heating period). As may be realized, the about 1 to about 2 minute warm up period and the about 2 minute to about 4 minute cool down period represents about 3 to about 6 minutes (5-10% of an hour) of furnace operation at lower efficiency than the rated steady state efficiency of the furnace 2000 so, for example, is a furnace 2000 is cycled on and off 3 to 5 times an hour (where, e.g., each cycle corresponds to a heat call from the thermostat), then about 15% to about 50% of the time the furnace 2000 is running, the furnace is running below its rated efficiency.

The heat recovery assembly/system 100 of the aspects of the disclosed embodiment include a multiple stage heat exchange system 120EX that is configured to recover heat lost during, for example, the warm up and cool down periods of the furnace. Further, in a conventional system the furnace is in an on state (e.g. burners FBRN lit) for 100% of the time during the heat call. The aspects of the disclosed embodiment described herein operate to discontinuously run the furnace 2000 in short bursts during a heat call so that the furnace 2000 is cycled on and off to achieve a higher efficiency by creating the start up and cool down furnace cycles/periods as frequently as, for example, 20 times per hour (based on, for example, a 1 hour long heat call) where, for example, during each 180 second cycle the burners FBRN are on for approximately 100 seconds and off for about 80 seconds so that heat is extracted/recovered during the start up and cool down periods, as described herein, to increase furnace efficiency and decrease fuel consumption. As will be described herein, during the furnace off times at least one stage of the multiple stage heat exchange system 120EX extracts residual heat from the furnace 2000 to balance a heat exchange to the supply air for heating the habitat (e.g. the multiple stage heat exchange system 120EX operates as a thermal balance to maintain a temperature of the supply air above a predetermined set point for heating the habitat during periods of the heat call where the furnace 2000 is turned off).

In one aspect, the assembly 100 includes a heat recovery chamber 110 which comprises a cooling intake 112 and an exhaust gas or emissions intake 114 for receiving exhaust gas and waste products emitted as a result of fuel combustion. It should be understood that while the heat recovery chamber 110 is illustrated in the figures as being cuboid in shape in other aspects the heat recovery chamber 110 has any suitable shape and/or configuration. For example, in other aspects, the heat recovery chamber 110 is a cylindrical drum, a pyramid or any other suitable shape. In one aspect, referring to FIG. 11, a portion of the heat recovery chamber 110B, such as a mixing portion 110C, may be integral with, for example, the exhaust gas intake 114 or any other suitable ducting so that exhaust from a furnace 2000 or boiler and cooling gas from cooling intake 112 is at least partially mixed within the ducting prior to contacting a heat exchanger, such as a first multiple stage heat exchanger 116 (which includes one or more heat exchange elements 116A, 116B), of the multiple stage heat exchange system 120EX, for recovering heat described below. In one aspect the heat recovery chamber 110 is an insulated chamber while in other aspects the heat recovery chamber 110 is uninsulated. The heat recovery chamber 110 is made from any suitable material such any suitable non-metallic material, plastics, PVC, ceramics, metals or alloys. In one aspect the heat recovery chamber 110 is made of stainless steel and/or titanium alloy.

The assembly 100 further includes a portion of the multiple stage heat exchange system 120EX such as the first multiple stage heat exchanger or absorber 116 (referred to herein as heat exchanger 116) noted above. In one aspect the first heat exchanger 116 is disposed within the heat recovery chamber 110 while in other aspects the first heat exchanger 116 is communicably coupled to the heat recovery chamber 110 in any suitable manner. For example, as described above with respect to FIG. 11, a pre-mixing/mixing chamber 110C, in one aspect, is integrated into any suitable ducting so that the exhaust gas and cooling gas are mixed (e.g. pre-mixed) prior contacting the first heat exchanger 116. In this aspect, illustrated in FIG. 11, the first heat exchanger 116 is disposed in a heat recovery chamber 110B that may be substantially similar to heat recovery chamber 110 however, the exhaust gas and cooling gas may be substantially combined prior to entering the heat recovery chamber 110B. Also referring to FIG. 12 the heat recovery chamber 110 constitutes a premix chamber 110A in which cooling gas from the cooling intake 112 and exhaust from the exhaust gas intake 114 mix or otherwise combine. The mixed gas flows into the heat exchange chamber 110B in which the first heat exchanger 116 is disposed. The first heat exchanger 116 includes one or more heat exchange elements 116A, 116B structured for contacting a mixture made up of cooling gas introduced via the cooling intake 112 and exhaust gas (e.g. made up of carbon emissions) introduced via the exhaust gas intake 114. In one aspect heat exchange element 116A is larger than heat exchange element 116B while in other aspects the one or more heat exchange elements 116A, 116B have any suitable size relationship with each other. In one aspect, one or more coil sensors CS1, CS2 are in contact with one or more of the heat exchange elements 116A, 1116B of the first heat exchanger 116 to relay any problems with the functionality (such as, for example, icing or frosting) of the one or more heat exchange elements 116A, 116B of the first heat exchanger 116 to a central logic board (discussed later herein) or any other suitable controller, such as controller 1311 (FIGS. 1 and 13) which is connected to the furnace controller 1311F in any suitable manner and is configured to operate the heat recovery assembly system 100 as described herein. In one aspect, the one or more heat exchange elements 116A, 116B of the first heat exchanger 116 are made from any suitable material, such as a metallic or non-metallic material that allows for an exchange of heat. In one aspect the one or more heat exchange elements 116A, 116B of the first heat exchanger 116 are constructed of, for example, metals and/or alloys, such as but not limited to, copper, aluminum and the like. In one aspect, the one or more heat exchange elements 116A, 116B of the first heat exchanger 116 is/are heat exchange coil(s) such as an evaporative coil(s) and/or use any suitable coolant or refrigerant such as a single phase coolant.

It should be understood that while the first heat exchanger 116 is illustrated as having two heat exchange elements 116A, 116B in FIG. 1, in other aspects the first heat exchanger 116 has more (see e.g. FIG. 1A) or less (see e.g. FIG. 10) than two heat exchange elements. For example, referring to FIG. 1A the heat recovery chamber 110 includes a first heat exchanger 116 that includes four heat exchange elements 116A, 116B, 116C, 116D disposed in sets of two (e.g. each set having a large and small heat exchange element or any suitably sized heat exchange elements as described above) having an opposing relationship so that gases passing through the heat recovery chamber 110 pass through one of the sets of heat exchange elements 116A, 116B, 116C, 116D. As may be realized, the recovery chamber 110, in one aspect, includes sub-chambers 110C1, 110C2. As can be seen in FIG. 1A the furnace exhaust and cooling gas are introduced into sub-chamber 110C1, flow through sub-chamber 110C1 and into sub-chamber 110C2 where the heat exchange elements 116A, 116B, 116C, 116D (e.g. of the stage one and stage two fluid circuits 120, 120A as described below) are located. Also referring to FIG. 1D, in one aspect the stage two fluid circuit 120A includes one heat exchange element 116B located in sub-chamber 110C1 while the heat exchange elements of the stage one fluid circuit 120 are located in the sub-chamber 110C2. It should also be understood that the one or more heat exchange elements 116A, 116B, 116C, 116D have any suitable arrangement within the heat recovery chamber 110. As may also be realized, each heat exchange element has, is part of a fluid circuit that is independently operable from other fluid circuits (e.g. each heat exchange element forms part of a separate stage of the multiple stage heat exchanger).

The cooling intake 112 has any suitable shape and/or configuration and in one aspect is structured as a single intake or in other aspects as multiple intakes. The cooling intake(s) 112 are configured to introduce one or more of indoor air or cooling gas (which is discharged from the heat recovery chamber 110 and recirculated) into the heat recovery chamber 110. In one aspect the cooling intake 112 is a closed loop extending from the chamber exhaust 118 to the heat recovery chamber 110 as described below. As will also be described below, in one aspect the cooling intake includes an active or passive orifice ORIF (which in one aspect includes a valve 112V—see FIGS. 1A and 13) that is opened and closed to direct any predetermined volume of cooling gas back to the recovery chamber 110. In one aspect about 50% of the gas exiting the recovery chamber is recirculated back to the recovery chamber 110 while in other aspects any suitable volume of gas is recirculated. In one aspect of the disclosed embodiment any suitable fans or blowers are provided in any suitable manner to generate a balanced pressure environment within the heat recovery chamber 110 as described herein. In another aspect one or more of the cooling intake(s) 112 are communicably connected to a pressure regulator inducer blower (also referred to herein as a fan) 140 (see e.g. FIG. 4) that may be part of any suitable pressure equalization system to assist in moving the gas inside the heat recovery chamber 110 out of the heat recovery chamber where a portion of the exhaust is directed out of the chamber exhaust 118 and a portion of the exhaust is directed to the cooling intake 112. In one aspect the inducer blower 140 is located on the exhaust side of the heat recovery chamber 110 as will described below while in other aspects the inducer blower is located at any suitable location. In one aspect the fan 140 includes a variable speed motor that is controlled by any suitable sensors in communication with an interior of the heat recovery chamber 110 and configured to detect proper temperature and/or humidity and/or pressure of the gas inside the heat recovery chamber 110.

In one aspect the one or more heat exchange elements 116A, 116B of the first heat exchanger 116 are interconnected in any suitable manner to a respective stage of a multi-stage fluid circuit system. For example, heat exchange element is connected to stage one fluid circuit 120 and heat exchange element is connected to stage two fluid circuit 120A (e.g. each heat exchange element is interconnected with a fluid circuit that is separate and distinct (e.g. independently operable) from other fluid circuits of other heat exchange elements where each fluid circuit has its own compressor 150, 150A) where the fluid circuits 120, 120A are any suitable fluid circuits. In other aspects the one or more heat exchange elements 116A, 116B are interconnected to a common fluid circuit such that coolant is shared between the one or more heat exchange elements 116A, 116B. The respective fluid circuit(s) 120, 120A include any suitable conduit 122, 122A for conveying fluid within the respective fluid circuit 120, 120A. The multiple stage heat exchanger system 120EX of the assembly 100 includes a second multiple stage heat exchanger or emitter 130 (e.g. a heat extraction exchanger) including one or more heat exchange elements 130A, 130B disposed exterior to the heat recovery chamber 110 such that each heat exchanger 130A, 130B of the second multiple stage heat exchanger 130 (referred to herein as heat exchanger 130) is in fluid communication with a respective fluid circuit 120, 120A via the respective conduit 122, 122A. In one aspect, heat exchange element 130A of the second heat exchanger 130 and heat exchange element 116A of the first heat exchanger 116 are communicably interconnected via the conduit 122 of the fluid circuit 120 such that the heat exchange element 116A of the first heat exchanger 116 contacts or otherwise interfaces with (e.g. within the heat recovery chamber 110 or in any other suitable manner as described herein) the mixture made up of cooling gas introduced via the cooling intake 112 and exhaust gas introduced via the exhaust gas intake 114, while the heat exchange element 130A of the second heat exchanger 130 contacts or otherwise interfaces in any suitable manner with air to be heated, outside of the heat recovery chamber 110. Similarly, heat exchange element 130B of the second heat exchanger 130 and heat exchange element 116B of the first heat exchanger 116 are communicably interconnected via the conduit 122A of the fluid circuit 120A such that the heat exchange element 116B of the first heat exchanger 116 contacts or otherwise interfaces with (e.g. within the heat recovery chamber 110 or in any other suitable manner as described herein) the mixture made up of cooling gas introduced via the cooling intake 112 and exhaust gas introduced via the exhaust gas intake 114, while the heat exchange element 130B of the second heat exchanger 130 contacts or otherwise interfaces in any suitable manner with air to be heated, outside of the heat recovery chamber 110. In other aspects, the heat exchange elements of the first and second heat exchangers 116, 130 are interconnected in any suitable manner. It should be realized, that while a two stage heat exchange system is illustrated and described in other aspects the heat exchange system has any suitable number of stages, such as more or less than two stages. As may also be realized, the heat exchange element 116A, fluid circuit 120 and heat exchange element 130A constitute the first stage of the multiple stage heat exchange system 120EX and the heat exchange element 116B, fluid circuit 120A and heat exchange element 130B constitute the second stage of the multiple stage heat exchange system 120EX.

Referring to FIGS. 1B and 1C the one or more heat exchange elements 130A, 130B of the second heat exchanger 130 are, in one aspect, condenser coils having any suitable size(s), shapes and/or arrangement. In one aspect the heat exchange element 130A includes two heat exchange elements 130A1, 130A2 coupled together in series to form a slab condenser coil. In one aspect, the two heat exchange elements 130A1, 130A2 of the heat exchange element 130A include vertical pipes and horizontal fins. In other aspects the heat exchange element is a single heat exchange element having horizontal pipe and vertical fins or vertical pipe and horizontal fins. The heat exchange element 130B is smaller than heat exchange element 130A and in one aspect includes horizontal pipes and vertical fins or vertical pipes and horizontal fins. As may be realized, the pipe and fin arrangement of the one or more heat exchange elements 130A, 130B is such that the pipes and fins of heat exchange element 130A intersect the pipes and fins of heat exchange element 130B (e.g. where heat exchange element 130A includes horizontal pipes and vertical fins the heat exchange element includes vertical pipes and horizontal fins) to facilitate a maximized heat transfer through the one or more heat exchange elements 130A, 130B.

In one aspect the heat recovery chamber 110 includes exhaust and drainage components. An exhaust 118 for discharging the exhaust gas (e.g. a portion of which is recirculated as cooling gas) after heat exchange occurs is configured or otherwise structured to interconnect, for example, the heat recovery chamber 110 to the outside environment and/or to cooling intake 112 for recirculating at least a portion of the exhaust gas (e.g. the cooling gas) back into the heat recovery chamber 110 as will be described in greater detail below. The heat recovery assembly/system 100 when combined with, for example, a furnace 2000 having about an 80% efficiency produces exhaust gas temperatures (As described herein) that enable the exhaust duct (e.g. exhaust 118) to be formed of PVC rather than metal of ceramic (e.g. effects the coupling of a PVC exhaust duct to the combination of the heat recovery assembly/system 100 and the furnace 2000). In one aspect, the exhaust 118 is a single two-inch pvc vent pipe while in other aspects the exhaust 118 has any suitable size and is constructed of any suitable material such as composites, metals, etc. In one aspect a drain 111 is connected to the heat recovery chamber 110 and is configured to carry condensate water WD that may include particulates, ash and/or soot out of the heat recovery chamber 110. In one aspect for example, a mister 113 is included in the heat recovery chamber 110, however in other aspects the mister 113 is not provided. The mister 113 is configured to saturate the gas within the heat recovery chamber 110 with moisture and to help capture and remove particulates, ash and/or soot from the exhaust gases in any suitable manner, such as by the particulates, ash and/or soot becoming saturated with water from the flash heat steam from, for example, the super heated oil combustion exhaust gas and falling to the bottom of the chamber to be discharged through the drain 111. In other aspects, the mister 113 may not be provided such that the condensate water WD is formed from moisture in the exhaust gas and/or cooling gas introduced through cooling intake 112 and helps capture and remove particulates, ash and/or soot from the exhaust gases. In one aspect a filter or other mechanical separation unit is provided to remove the particulates, ash and/or soot from the condensate water WD discharged through the drain 111. Where the mister 113 is provided the mister 113 is, in one aspect, connected to a pressurized water tube to provide water to the heat recovery chamber 110 to raise the dew point within the heat recovery chamber 110 to raise the heat transfer potential.

The aspects of the disclosed embodiment illustrated in FIG. 1 are designed for use when the exhaust gas input through the exhaust gas intake 114 originates from the burning of cleaner burning propane or other natural gases, such as but not limited to, a natural gas-burning furnace component of a heating, ventilation and air conditioning (HVAC) unit. However, it should be understood by those skilled in the art that the assembly 100 could be utilized in other situations where the surrounding air is to be heating by fossil fuel combustion.

FIG. 2 illustrates an aspect of the disclosed embodiment of the assembly 100 that may be used when the exhaust gas input to the heat recovery chamber 110 through the exhaust gas intake 114 originates from an oil-burning furnace. As may be realized, this aspect of the disclosed embodiment may also be used when the exhaust gas input to the heat recovery chamber 110 through the exhaust gas intake 114 originates from burning of natural gas as well. The components and configuration of this aspect of the disclosed embodiment are generally the same as in FIG. 1; however, additional aspects are included for capturing the heat that is stored in the condensate water WD that may accumulate within, such as at the bottom, of the heat recovery chamber 110. While the capturing of heat stored in the condensate water WD is described with respect to the heat recovery chamber 110 in FIG. 2 it should be understood that, in other aspect, capturing heat stored in condensate water WD in the heat exchange chamber 110B (see e.g. FIGS. 11 and 12) is provided in a manner substantially similar to that described herein. In other aspects heat captured in the condensate water WD may be recovered from the heat recovery chamber 110, 110B. The aspects of the disclosed embodiment illustrated in FIG. 2 include a third heat exchanger 117 in fluid communication with one or more of the first heat exchanger 116 and the second heat exchanger 130 via a second conduit 124 for absorbing the excess heat stored in the water as it accumulates from the condensate water WD produced within the heat recovery chamber. Since the second conduit 124 is in communication with one or more of the first heat exchanger 116 and the second heat exchanger 130, the third heat exchanger 117 may be further in fluid communication with one or more of the fluid circuits 120, 120A as a whole. The drain 111 in FIG. 2 is shown, for exemplary purposes, to be structured such that condensate water WD and ash/soot within the condensate water WD does not drain from the heat recovery chamber 110 until the water rises to a certain level, WL. This allows the third heat exchanger 117 to remain underneath the surface of the condensate water WD as it absorbs the excess heat energy stored in the condensate water WD so that very little, or none, of the heat energy remains unabsorbed in the entire process (e.g. substantially all heat energy is extracted from the condensate water WD).

During operation of the assembly and/or system of the disclosed embodiment, hot exhaust gases and combustion products (carbon monoxide, carbon dioxide, H20, etc.) are exhausted into the heat recovery chamber 110. In one aspect, one or more of indoor air and cooling gas is introduced into the heat recovery chamber 110 in any suitable manner to mix with the hot exhaust gas. A large, cubic footprint of gas is saturated and heated as a result of the mixing. This mixture flows across one or more heat exchange elements 116A, 116B of the first heat exchanger 116 while the dew point rises, holding water and heat (saturation). The heat is extracted from the mixture via the one or more heat exchange elements 116A, 116B of the first heat exchanger 116 (and third heat exchanger 117 when provided) and transferred to a respective one of the one or more heat exchange elements 130A, 130B of the second heat exchanger 130 such that heat transfer occurs at the one or more heat exchange elements 130A, 130B of the second heat exchanger 130 to heat, for example, indoor air or any other suitable medium. Cooler, dry gas from the heat recovery chamber 110 is exported outdoors in any suitable manner, such as through any suitable chimney or exhaust flue, with a reduced heat, moisture and carbon content. In addition, as described herein, at least a portion of the cooler, dry gas from the heat recovery chamber 110 is recirculated (e.g. as cooling gas) back into the heat recovery chamber 110. This process allows heat energy to be pulled from the gas introduced into the heat recovery chamber such that it is compounded with the heat energy already being produced by the fossil fuel combustion process. This provides the assembly and system described herein in accordance with the aspects of the disclosed embodiment the potential to achieve a higher efficiency of fuel burn.

By way of example and referring to FIG. 3, aspects of the disclosed embodiment of the heat recovery assembly/system 100 are illustrated with respect to an exemplary 80% annual fuel utilization efficiency (AFUE) furnace rated at 100,000 input/80,000 output. Hot, moist exhaust gases are extracted from the furnace at approximately 375° F. with approximately 90% plus humidity at approximately 55 CFM. In other aspects the exhaust gases have any suitable temperature and humidity and are extracted at any suitable rate. The hot, water-saturated, exhaust gas carries a large heat potential (of e.g. at least 20,000 British Thermal Units per Hour (BTUH)). In addition to heat energy, the water-saturation of the exhaust gas (e.g. misting may increase this water-saturation where provided) includes high levels of potential energy for extraction. These exhaust gases are mixed with dry, cool gas (e.g. the cooling gas) of equal cubic feet per minute (CFM) using, for example, pressure regulation in the heat recovery chamber 110. In one aspect the cool dry gas (e.g. cooling gas) is obtained from the discharge 118 of the heat recovery chamber 110 (as shown in, for example, FIG. 4A) where after heat extraction at least a portion of the discharge exhaust gas is returned to the heat recovery chamber 110 under the influence of a fan 140. Referring also to FIG. 4 the pressure regulation of the heat recovery assembly 100 effected by a balanced pressure system where the fan 140 is placed downstream of the heat recovery chamber 110 so as to draw or suck the gasses out of the heat recovery chamber 110. In one aspect, the fan 140 is sized so as to be substantially equal to two-times the cfm of the furnace inducer fan motor so that the discharged exhaust gas from the heat recovery chamber is split so that substantially half the discharged exhaust gas (e.g. cool dry gas or cooling gas) is returned to the heat recovery chamber to cool and be mixed with the gases from the furnace 2000 that enter the heat recovery chamber through gas intake 114. In other aspects, the fan 140B is sized to recover any suitable portion of the discharged exhaust gas from the heat recovery chamber for mixing with and cooling the gases from the furnace 2000 input to the heat recovery chamber 110 through gas intake 114. As may be realized, mixing the gases from the furnace with the cooling gas from the heat recovery chamber 110 substantially eliminates any influence of fluctuating outdoor temperatures on the heat recovery assembly 100 and substantially isolates the furnace from outdoor pressure/wind influences. As may be realized, the fan(s) 140 are controlled in any suitable manner, such as by controller 1311 and/or by a rheostat to allow balancing of gas flow volume and velocity through the heat recovery assembly 100.

Within the heat recovery chamber 110 under controlled conditions, in one aspect, the cooling gas, described herein, is saturated by the misted water within the exhaust gas, resulting in an increase in the dew point while in other aspects the cooling gas is not misted. The heat energy released in the exhaust gas (which may have a temperature of approximately 375° F. or any other suitable temperature) mixes with the cooling gas, resulting in a mean temperature of approximately 160° F. (or any other suitable temperature). The combined gases include oxygen (O₂) assisting in the heat transfer process. The combined gases are a warm (about 160° F. or other suitable temperature), high dew point gas having, for example, a high-energy potential for high efficiency heat and energy extraction.

This combined gas mixture passes over one or more of the heat exchange elements 116A, 116B of the first heat exchanger 116. The fluid, e.g. refrigerant, in the one or more heat exchange elements 116A, 116B of the first heat exchanger 116 is under controlled pressurized conditions and is able to extract a large amount of heat energy from the combined gas mixture and transfer the heat energy to the a respective one of the one or more heat exchange elements 130A, 130B of the second heat exchanger 130 via the respective fluid circuit 120, 120A such that the transferred heat energy warms the indoor air as the indoor air flows over the one or more heat exchange elements 130A, 130B of the second heat exchanger 130. The flow of refrigerant in the fluid circuit 120, 120A between each of the components of the assembly is illustrated by arrows in FIG. 3. The exhaust gas discharged from the heat recovery chamber following the controlled and regulated mixing within the heat recovery chamber 110 may be dry, cool exhaust gas. For exemplary purposes, the average discharged exhaust gas from the heat recovery chamber 110 has a temperature of about 42° F. to about 49° F., a humidity of about 10%, and about a 0.05-0.00 PPM CO (carbon monoxide) content. In one aspect one or more suitable thermostat or temperature sensor TS is mounted on the furnace supply plenum or duct 1301 (and/or on the furnace return plenum 1300) and is positioned outside of any thermal influence of the heat that radiates from the thermal mass of the one or more heat exchange elements 130A, 130B. The thermostat TS is connected to the controller 1311 in any suitable manner so as to effect operation of the heat recovery system 100 as described herein.

Still referring to FIG. 3 and also to FIGS. 18A-18C, an operation of the heat recovery assembly and systems described herein is described in greater detail. In one aspect the controller 1311 is in a monitoring state that monitors a state of the furnace 2000 and one or more thermostats TSH that control the heating in one or more heating zones of a building or other area to be heated (FIG. 18A, Block 9000). When the one or more thermostats TSH detect a temperature that is less than a predetermined set temperature of the thermostat TSH the thermostat sends any suitable signal to the controller 1311. The controller 1311 detects the signal and the heat call embodied in that signal (FIG. 18, Block 9001). The controller 1311 is, in one aspect, configured to determine if the heat call is a false alarm. Where the heat call is a false alarm the controller 1311 returns to the monitoring state (FIG. 18, Block 9002). Where the heat call is valid the controller 1311 forwards the heat call to the furnace controller 1311F to effect turning the furnace 2000 and the fan 140 on (FIG. 18A, Block 9003). The controller 1311 is also configured to determine if the heat call remains active (FIG. 18A, Block 9005). In one aspect, the controller 1311 waits any suitable predetermined time period before determining if the heat call remains active (FIG. 18A, Block 9004). If the heat call is no longer active the controller 1311 turns the furnace 2000 off (FIG. 18A, Block 9006) by sending any suitable signal to the furnace controller 1311F and returns to the monitoring state (FIG. 18A, Block 9007). Where the heat call remains active the controller 1311 turns on compressor 150 (FIG. 18A, Block 9008) and compressor 150A (FIG. 18A, Block 9009). In one aspect, the controller 1311 waits any suitable predetermined amount time period between the starting of compressor 150 and the starting of compressor 150A. The controller 1311 determines if the heat call remains active (FIG. 18A, Block 9010). Where the heat call is inactive the controller 1311 turns the furnace 2000, the fan 150, 150A and the compressors 150, 150A off (FIG. 18A, Block 9011) and returns to the monitoring state (FIG. 18A, Block 9012). Where the heat call remains active controller proceeds to an active state (FIG. 18A, Block 9014). In one aspect the controller waits any suitable predetermined time period before proceeding to the active state (FIG. 18A, Block 9013).

In the active state the controller 1311 monitors whether the thermostat TSH temperature is satisfied (FIG. 18B, Block 9015). Where the thermostat TSH temperature is satisfied the controller 1311 turns the compressors 150, 150A, the fan 140 and the furnace off (FIG. 18B, Blocks 9016, 9018) and returns to the monitoring state 9019. In one aspect the controller 1311 waits any suitable time period before turning the fan 140 off (FIG. 18B, Block 9017). If the thermostat TSH temperature is not satisfied the controller determines, from any suitable temperature sensors whether the one or more heat exchange elements, such as heat exchange elements 116A, 116B, require defrosting (FIG. 18B, Block 9020).

If one or more heat exchangers require defrosting the controller 1311 determines if the call for defrosting is valid such that if the call for defrosting is not valid the controller 1311 returns to the active state (FIG. 18B, Block 9021). Where the call for defrosting is valid the controller 1311 turns the compressor(s) 150, 150A off (FIG. 18B, Block 9022), waits a predetermined amount of time suitable for defrosting (e.g. a defrost cycle) the one or more heat exchange elements 116A, 116B (FIG. 18B, Block 9023) and returns to the monitoring state (FIG. 18B, Block 9024). If the thermostat heat call is satisfied during the defrost waiting period the defrost cycle ends and the controller 1311 returns to the monitoring state (FIG. 18B, Block 9025). Where there is no call for defrosting the one or more heat exchange elements 116A, 116B the controller 1311 determines if the furnace 2000 has failed (FIG. 18B, Block 9026).

Where the controller receives a furnace fail call from, for example, any suitable sensors connected to the furnace, the controller 1311 determines if the furnace fail call is valid and if the furnace fail call is not valid the controller 1311 returns to the active state (FIG. 18B, Block 9027). If the controller 1311 determines that the furnace fail call is valid the controller 1311 turns the compressor(s) 150, 150A and the furnace 2000 off (FIG. 18B, Block 9028) and waits a predetermined period of time (FIG. 18B, Block 9029) before turning the fan 140 off (FIG. 18B, Block 9030) and returning to the monitoring state (FIG. 18B, Block 9031). Where there is no furnace fail call the controller determines if the heat recovery assembly 100 has failed (e.g. the controller receives a heat recovery assembly fail call from any suitable sensors connected to the heat recovery assembly 100) (FIG. 18B, Block 9032).

Where the controller receives a heat recovery assembly fail call the controller 1311 determines if the heat recovery assembly fail call is valid and if the heat recovery assembly fail call is not valid the controller 1311 returns to the active state (FIG. 18B, Block 9033). If the controller 1311 determines that the heat recovery assembly fail call is valid the controller 1311 turns the compressor(s) 150, 150A and the furnace 2000 off and turns the fan 140 on (FIG. 18B, Block 9034). The controller effects any suitable aural and/or visual alert indicating a reset of the heat recovery assembly 100 is needed (FIG. 18B, Block 9035) and when the heat recovery assembly 100 is reset the controller 1311 returns to the monitoring state (FIG. 18B, Block 9036). If there is no heat recovery assembly fail call the controller 1311 enters a heat cycle mode (FIG. 18B, Block 9037).

As described above, a temperature sensor TS is mounted on or within the furnace supply plenum or duct 1301 of the furnace 2000. When the furnace 2000 is burning gas (e.g. is turned on) the heat recovery assembly 100 is extracting heat from the furnace exhaust gas and preheating the air in the return plenum 1300 so that hot air is produced at elevated temperatures compared to the furnace 2000 running by itself. The sensor TS is monitored by the controller 1311 (FIG. 18C, Block 9038) and is set to trigger or otherwise send a signal to the controller at any suitable predetermined high temperature threshold or set point, such as about 130° F. (in other aspects the high temperature threshold is more or less than 130° F.). When the controller 1311 receives a signal from the temperature sensor TS that the high temperature threshold is reached the controller interrupts the thermostat TSH heat call which closes the furnace fuel valve FV and shuts off the burners FBRN (e.g. turns the furnace off however, the blower FIB remains running for a predetermined period of time per furnace programming as described herein) and turns the stage 2 compressor 150A off (FIG. 18C, Block 9039). In this aspect, the heat recovery assembly 100 leverages the furnace programming (e.g. incorporates the embedded furnace controller 1311F that continues to run the blower FIB for a predetermined period of time, as described above, after the burners FBRN are turned off) and continues to extract and transfer heat from the residual heat from the furnace 2000 in the chamber 110 and into the supply air stream (e.g. the blower FIB continues to operate so that air moves over/through the heat exchanger(s) 130A, 130B, FHX while the heat being transferred from the heat exchanger 116A decreases). As may be realized, the temperature sensor TS in the supply plenum 1301 is further configured to send a signal to the controller 1311 indicating a predetermined low temperature threshold or set point, such as about 100° F. (in other aspects the low temperature threshold is more or less than 100° F.) The controller 1311 monitors the temperatures sensor TS for a low temperature threshold signal (FIG. 18C, Block 9040) and if the low temperature threshold signal is received by the controller 1311, the controller 1311 reinstates the thermostat TSH heat call so that the furnace 2000 and the stage 2 compressor 150A are turned on (FIG. 18C, Block 9041) and the process returns to block 9038 so that the furnace is discontinuously run in short bursts so that the furnace is cycled between the on and off states during the heat call. As may be realized, the low temperature threshold is such that the low temperature threshold is reached before the blower FIB turns off so that air is continually circulating through the furnace heat exchanger FHX for delivering heat to the supply air during the heat call whether the burners FBRN are lit or off. In other aspects, the controller 1311 includes any suitable programming for turning the burners FBRN back on prior to the blower FIB being turned off (e.g. if the low temperature threshold is not met or for any other suitable reasons). If the low temperature threshold signal is not received the controller 1311 monitors the furnace blower timeout (e.g. the period of time the blower FIB operates after the burners FBRN are turned off) (FIG. 18C, Block 9040A). If a predetermined time period prior (e.g. any suitable time period such as seconds before the expiration of the timeout, a minute before the timeout, etc.) to the timeout period expiring has not been reached (FIG. 18C, Block 9040B) the controller 1311 continues to monitor for the low temperature threshold signal. If the predetermined time period prior to the timeout period expiring has been reached (FIG. 18C, Block 9040B) the controller 1311 reinstates the thermostat TSH heat call so that the furnace 2000 and the stage 2 compressor 150A are turned on (FIG. 18C, Block 9041) and the process returns to block 9038 so that the furnace is discontinuously run in short bursts so that the furnace is cycled between the on and off states during the heat call.

If the thermostat TSH heat call is satisfied the controller 1311 returns to the monitoring state and the furnace 2000, compressor(s) 150, 150A and fan 140 are turned off (FIG. 18C, Block 9042). As may be realized, the monitoring of the temperature sensor TS in the supply plenum 1301 effects a repeating on/off cycling of the furnace burners FBRN (e.g. the furnace is cycled between being turned on and being turned off) until the thermostat TSH heat call is satisfied which shuts the furnace 2000 and the heat recovery assembly 100 down until the next thermostat TSH heat call. In other words, the controller 1311 is coupled to the temperature sensor TS having predetermined hi and low temperature set points and is configured or otherwise programmed so that in response to the heat call from the thermostat TSH the furnace is repeatedly cycled (e.g. run discontinuously or turned on and off) when the controller 1311 registers the temperature sensor TS signal corresponding to the hi temperature set point (e.g. the furnace is turned off) and the low temperature set point (e.g. the furnace is turned on).

The following is an exemplary table illustrating tests performed on various furnaces where the input/size is the btu rating of the furnace tested, cfm is the amount of air moved by the furnace tested, target is the targeted btus from the heat recovery assembly/system 100 to be added to the furnace heat output, the cycles per hour is the number of times the furnace tested was discontinuously run (e.g. turned on and off) over a one hour heat call, the average supply temperature (° F.) is the average temperature of the air passing through the return plenum 1300 during both furnace on and off states/periods, the average return temperature (° F.) is the average temperature of the air returning to the return plenum 1300 during both furnace on and off states/periods, the average delta temperature (° F.) is the difference between the average supply temperature and the average return temperature, the added btus are the btus recovered by the heat recovery assembly/system 100 described herein and the fuel btus is the amount of btus obtained from burning fuel during furnace on states/periods, efficiency is the fuel conversion efficiency of the furnace with the heat recovery assembly/system 100, variation is the difference between the target btus and the added btus, on second refers to the amount of time the furnace was in the on state during each cycle of the discontinuous furnace operation, off seconds refers to the amount of time the furnace was in the off state during each cycle of the discontinuous furnace operation, therms is the amount of heat energy from fuel burned (e.g. the fuel btus), latent refers to an amount of heat (btus) of entrained water and recovered by the heat recovery assembly/system 100 throughout the heating cycle, source is the amount of heat (btus) recovered by the heat recovery assembly/system 100 during furnace operation, and residual is the amount of heat (btus) recovered by the heat recovery assembly/system 100 during furnace cool down periods.

Average Average Average Input/ Cycles supply return delta Furnace size Cfm Target per hour temp temp temp 2 60000 1150 48000 13.90 120.3 64.8 55.5 1 88000 1210 70400 19.40 116.1 66.6 49.5 4 100000 1674 80000 23.50 115.4 67.1 48.3 6 120000 1513 96000 29.00 124.9 67.7 57.2 5 140000 1500 112000 23.00 140.5 71.6 68.9

Added Fuel On Off Furnace btus btus Efficiency Variation seconds seconds 2 72122 35900 200.9% 24122  115 150 1 67695 35180 192.4% (2705) 110 85 4 91365 62720 145.7% 11365  95 55 6 97794 64910 150.7% 1794 65 50 5 116786 73800 158.2% 4786 95 55

Furnace therms latent source residual 2 0.3590 2901 35900 33321 1 0.3518 2843 35180 29672 4 0.6272 5068 62720 23577 6 0.6491 5245 64910 27639 5 0.7380 5963 73800 37022

It is noted that all values in the above table are approximate and provided for exemplary purposes only. As can be seen from the above table, the discontinuous operation (e.g. cycling between on and off states) of the furnace during a heat call decreases an amount of fuel used during the heat call while the heat recovered during the latent, source and residual heating periods by the heat recovery assembly/system 100 increases the fuel conversion efficiency of the furnace 2000.

During the latent, source and residual heating periods (e.g. respectively the period where the furnace 2000 is warming the furnace heat exchanger FHX, the periods the furnace is on and the periods where the furnace 2000 is turned off during the heat call) one or more stages of the multiple stage heat exchanger 120EX operate as described herein to increase, balance or otherwise continue heat transfer to the return air travelling through the return plenum 1300 for heating the supply air delivered to the habitat through the supply plenum 1301. For example, in accordance with aspects of the disclosed embodiment, the stage one compressor 150 runs substantially 100% of the time (e.g. when the furnace is on and when the furnace is off) the during a full thermostat heat call cycle (e.g. a duration of the heat call) so as to extract heat (e.g. residual furnace heat) from the chamber 110 and transfer heat to the supply air. In one aspect the secondary compressor 150A only runs while the furnace is turned on (e.g. the furnace burners FBRN are lit) while in other aspects the secondary compressor 150A also runs when the furnace burners FBRN are not lit (e.g. the furnace is turned off). In other aspects, the first and second stages of the heat exchange system are operated at any suitable times, either together or individually, during the heat call. For example, in one aspect, only stage one operates during furnace off times and only stage two operates during furnace on times or vice versa. In another aspect, stage one operates to a point where a temperature of the supply air reaches a predetermined temperature at which time stage one is turned off and stage two is turned on, or vice versa. In one aspect, the controller 1311 is configured to stagger a starting of the stage one compressor 150 and the stage one compressor 150A to, for example, avoid a combined electrical surge of the compressors 150, 150A.

As may be realized, the heat recovery assembly/system 100 described herein is adapted to attach to or otherwise interface with any suitable furnace having any age or configuration. In one aspect the assembly 100 may be attached to a furnace with about 78% AFUE or higher efficiency, resulting in an increased efficiency of the system. Carbon discharge, exhaust gas temperature, and humidity may also be reduced if the assembly 100 is employed with a furnace.

Still referring to FIGS. 1 and 3, in one aspect a pressure sensors S2 is placed in the heat recovery chamber exhaust 118 and is connected to the controller 1311 in any suitable manner (such as through a wired or wireless connection). The pressure sensors S2 is configured to monitor an exhaust vent pressure of the furnace 2000 and/or heat recovery assembly 100 and send any suitable signal to the controller to turn the furnace off if the exhaust vent pressure exceeds a predetermined pressure and to turn the furnace back on if he exhaust vent pressure falls below the predetermined pressure. The controller 1311 is configured to, based on the signals from the sensor S2, to turn off the furnace 2000 by interrupting the heat call from the thermostat TSH. In one aspect, a temperature sensor S3 is disposed in the heat recovery chamber exhaust 118 and is connected to the controller 1311 for monitoring the exhaust gas exiting the heat recovery chamber. Where the sensor S3 detects the exhaust gas has a temperature above any suitable predetermined threshold temperature the controller 1311 is configured to, based on the sensor S3 signals, turn off the furnace 2000 by interrupting the heat call from the thermostat TSH. In one aspect, a temperature sensor S1 is disposed in the furnace exhaust 2100/intake 114 and is connected to the controller 1311 for monitoring a temperature of the exhaust gas entering the heat recovery chamber from the furnace 2000 (or in other words monitoring of the exhaust gas exiting the furnace 2000). Where the sensor S1 detects the exhaust gas from the furnace 2000 passing through the intake 114 is below a predetermined temperature threshold the controller 1311 is configured to, based on the sensor S1 signals, turn off the compressor(s) 150, 150A to protect the compressor(s) 150, 150A and substantially prevent freezing of the heat exchange elements 116A, 116B. In one aspect each fluid circuit 120, 120A includes a temperature sensor S5, S6 for monitoring a temperature of the cooling fluid within the respective fluid circuit 120, 120A. The temperature sensors S5, S6 are connected to the controller 1311 and suitable signals to the controller when, for example, a low temperature threshold is met so that the controller 1311 effects a defrosting of the heat exchange elements 116A, 116B in any suitable manner.

Referring next to FIG. 5 and FIG. 10, a heat recovery system 200 is illustrated in accordance with aspects of the disclosed embodiment. The system 200 may include a furnace 2000 comprising an exhaust 2100 and a furnace intake 2300. The system 200 further includes heat recovery chamber 110 having a cooling intake 112 and an exhaust gas intake 114. In other aspects the system 200 may include a premix chamber 110A, 110C and a heat exchange chamber 110B as described above with respect to FIGS. 11 and 12. The exhaust gas intake 114 may be configured to be communicably coupled to (e.g. in communication with) the exhaust 2100 of the furnace to receive exhaust gas resulting from fuel combustion in the furnace 2000. A first heat exchanger 116A may be disposed within the heat recovery chamber 110 and is in fluid communication with a fluid circuit 120 that includes a conduit 122 configured to convey a fluid therein, such as a refrigerant. In other aspects the first heat exchanger 116, which includes heat exchange element 116A, may be communicably disposed outside the heat recovery chamber. The first heat exchanger 116 may be configured such that during operation of the furnace 2000 it is in thermal communication with a mixture comprising cooling gas introduced via the cooling intake 112 and exhaust gas introduced via the exhaust gas intake 114 that is connected to the furnace exhaust 2100.

The system 200 may include a second heat exchanger 130, which includes heat exchange element 130A, in fluid communication with the fluid circuit 120 and disposed in thermal communication with an airstream being drawn into the furnace for heating (see INDOOR AIR passing through the second heat exchanger 130 in FIG. 5). Refrigerant is heated in the first heat exchanger 116 and moved to the second heat exchanger 130 via the pressure gradient created by the heat exchange and, optionally, with assistance from any suitable compressor such as the micro-compressor or the like (as described above), where heat exchange occurs between the airstream flowing from the indoor air source and the second heat exchanger 130. The pre-heated air from the second heat exchanger 130 is directed into the heat exchanger 2200 of the furnace such that the air is further heated and then directed into the home or other habitable structure for heating the home or other habitable structure.

The system 200 may include a drain 111 exiting the heat recovery chamber 110. The drain 111 may be substantially similar to that described above and structured as, for example, in FIG. 1 or FIG. 2, depending on the type of furnace being utilized in the system 200 (as explained previously herein). As may be realized, a system 200 including the drain 111 as illustrated in FIG. 2 would include a third heat exchanger 117 as previously described herein.

The system 200 may also include any suitable compressor 150 that may be substantially similar to that previously described herein. In one aspect the compressor may be a micro-compressor to aid in energy conservation. In another aspect a furnace inducer blower, IB, may be in connection with the furnace exhaust 2100 to actively draw exhaust from the furnace 2000 into the exhaust gas intake 114 of the heat recovery chamber 110.

The assembly 100 and system. 200 of the disclosed embodiment may further include a heat recovery ventilator. Heat recovery ventilators have been a known art in the HVAC industry for many years; however, the typical ventilator is much less efficient and structurally different than the aspects of the disclosed embodiment in combination with the assembly and system herein. A conventional Heat Recovery Ventilator (HRV) draws in fresh outdoor air to replace exhausted indoor air. The HRV helps create air exchanges within home or building structures which in turn helps to reduce pollutants, smoke, contaminants, airborne allergies, viruses, etc. from collecting within the home or building ventilation systems. During the air exchange process of a ventilator, fans and heat exchangers will pass heated or cooled indoor air over unconditioned outdoor air. The two air masses never combine but are separated by heat exchangers. This process can transfer as much as 85% of the heat energy from the conditioned air mass to the unconditioned air mass. About 15% of the energy is lost in this process, causing the home or building owner the expense of heating or air conditioning that loss to the newly introduced unconditioned air in order to maintain the same comfort level within the structure.

Referring to FIGS. 5A and 10A a heat recovery system 200′ is illustrated in accordance with aspects of the disclosed embodiment. The heat recovery system 200′ is substantially similar to heat recovery system 200 described above with respect to FIGS. 5 and 10 however, in this aspect the heat recovery system also includes the stage two cooling circuit 120A as described above. As such, the first heat exchanger 116 of the heat recovery system 200′ includes heat exchange elements 116A and 116B disposed in the heat recovery chamber 110 and the second heat exchanger 130 includes heat exchange elements 130A and 130B through which the indoor air passes for pre-heating the indoor air. As can be seen in FIG. 5A the cool, dry exhaust gas (e.g. cooling gas) introduced in the heat recovery chamber through cooling intake 112 is, in one aspect mixed with recovery indoor air introduced into the cooling intake 112 in any suitable manner such as by any suitable fan while in other aspects, the recovery air is omitted. It is also noted that the fan or blower 140 is positioned to suck or draw the gases through the heat recovery chamber 110 while in other aspects, the fan is located in any suitable location for moving the gases through the heat recovery chamber 110.

FIG. 6 illustrates a heat recovery ventilator (HRV) assembly 160 configured in relation to a heat recovery assembly 100 for providing fresh outdoor air to the interior environment in accordance with aspects of the disclosed embodiment. The HRV contains a ventilator outdoor air intake 162 that is structured to be in communication with the second heat exchanger 130 for heating outdoor air as it is drawn into the air intake of a heating apparatus or furnace. The HRV provides clean, outdoor air for circulation within the home or building. It directs the air into the airstream being drawn across the second heat exchanger 130 such that it can be heated by the energy efficient process of the heat recovery assembly 100 or system 200, as previously described herein. In one aspect the HRV assembly 160 may include a motorized damper 164 in communication with the outdoor air intake 162 such that the flow of outdoor air is regulated. A thermostat 166 may be in communication with the motorized damper 164 for controlling the opening and closing of the damper 164 based on the outdoor air temperature. In one aspect the damper 164 may allow air temperatures ranging from about 10° F. to about 70° F. to pass therethrough. In other aspects the damper 164 may allow air having any suitable temperature to pass therethrough. The thermostat 166 may include a temperature sensor 168 to communicate the outside air temperature. In one aspect the inducer blower, such as fan or blower 140B is located on an outlet side (e.g. on a side of the heat exchanger where the combined cooling gas and exhaust gas exit from the heat exchanger) of the heat recovery chamber 110 so that gas is “pulled” through the first heat exchanger 116 while in other aspects the fan is located at any suitable location for moving gas through the heat recovery chamber.

FIG. 7 illustrates an electrical wiring diagram of a heat and energy recovery system in accordance with aspects of the disclosed embodiment. The diagram illustrates the connections between a logic board or other suitable controller 1311 of the system and the furnace control board and thermostat of an HVAC system. In one aspect, the logic board or controller 1311 may include a LCD scroll display 171 for a visual depiction of the operational parameters of the system. Heat recovery, troubleshooting, and normal operating conditions may be indicated by LED lights (see “POWER”, “TROUBLE”, “COMP1” and “COMP2”) or in any other suitable visual and/or aural manner. Various connections between sensors and switches (e.g., low and high pressure switches) are also depicted. The inducer blower or fan and micro-compressor connections and requisite relays are also depicted but may not be provided such as when the system does not include an inducer blower or compressor. Connections between one or more components of the system may be wired with the controller 1311 to provide centralized control and functionality of the system.

FIGS. 8A, 8B and 9 illustrate operational aspects of the heat and energy recovery system 200 with a furnace 2000 in accordance with the disclosed embodiment. As shown, the system 200 may be adapted to fit on the furnace unit either on a wall of the unit (FIG. 8A) or inline with the air intake (e.g. return plenum) of the furnace (FIG. 9). In other aspects the system 200 may have any suitable positional relationship relative to the furnace 2000. A cut-away illustration is shown in FIG. 10 where, in one aspect of the disclosed embodiment, the system 200 is structured to be inline with the furnace intake 2300 (which is substantially similar to return plenum 1300) for receiving air as it is drawn into the furnace 2000. As can be seen in FIG. 8A, different configurations with respect to the placement of the return plenum 1300, the recovery chamber 110 and the first and second heat exchangers 116, 130 relative to the furnace 2000.

In one aspect the heat recovery system 100, 200, 200′ may substantially be a modular unit that can be connected to, for example, furnace 2000 having a common housing 200HA (such as that shown in FIG. 9) in which at least the first and second heat exchangers 116, 130 are located. In one aspect the heat recovery system 100, 200, 200′ has a two part modular configuration such that the first heat exchanger 116 is included in one modular 200A unit having a first housing 200HB and the second heat exchanger is included in another modular unit 200B having a second housing 200HC that can be placed at different locations relative to each other and/or the furnace 2000 or boiler such as illustrated in FIG. 8A. In other aspects the heat recovery system 100, 200, 200′ includes more than two modules where each module includes one or more of the heat exchange elements of the first and second heat exchangers 116, 130, for example, additional heat exchangers and/or other components of the heat recovery system 100, 200 may be disposed in respective modular units each having a respective housing for placement at any suitable location relative to other modular units. Also referring to FIG. 8B the modular unit 200A may include the first heat exchanger 116, the recovery chamber 110 and any other suitable components of the heat recovery system 100, 200, 200′ such as one or more of the features illustrated in FIGS. 7, 7A and 7B. The modular unit 200B may include the second heat exchanger 130 disposed within housing 200HC. As can be seen in FIG. 8B the modular units 200A, 200B may be placed at any suitable locations relative to each other and/or the furnace 2000 (or boiler) which in one aspect may depend on available space in the installation location of the heat recovery system 100, 200.

Referring to FIG. 15, in one aspect of the disclosed embodiment, at least a portion of the heat recovery system may be integrated within a housing 2000H of the furnace 2000. For example, in one aspect the housing 2000H may house combustion chamber 2000CH and at least the first heat exchanger 116 so that the furnace 2000 has an integral refrigerant heat exchange. In one aspect the first heat exchanger may be disposed within a heat exchange chamber 110B (e.g. substantially similar to that described with respect to FIG. 12) where a gas inlet is provided at least partly in the housing 2000H for transferring combined exhaust gas and cooling gas to the first heat exchanger from the exhaust gas inlet 114 and cooling intake 112. In other aspects the first heat exchanger 116 may be disposed within the heat recovery chamber 110 (which is disposed within the housing 2000CH) while in other aspects the heat recovery chamber 110, 110B may be separate from a heat exchange chamber 110B (where the first heat exchanger is located within the heat exchange chamber 110B) as described above with respect to FIGS. 11 and 12. As may be realized, the heat recovery chamber 110, 110B and the heat exchange chamber 110B may be disposed within the housing 1200CH such that the exhaust inlet 114 and cooling intake 112 (located at least partly within the housing) provide exhaust gas and cooling gas to the combining chamber. In one aspect, the housing may also house the second heat exchanger 130 that is communicably connected to the first heat exchanger through one or more of conduits 120, 120A.

Referring to FIG. 13 a modular heat recovery system is shown in accordance with the aspects of the disclosed embodiment. In this aspect the return plenum 1300 returns air from the heating space to the furnace to be heated. In one aspect outdoor or ventilation air may be introduced to the return air through duct 1303 which may include a blower or fan (in other aspects a fan may not be provided) for moving the outdoor air into the return plenum 1300. The modular unit 200B may be located, for example, between the furnace 2000 and the return plenum 1300, within an internal passage of the return plenum 1300 and/or in-line with the return plenum 1300. As described above, heat from the second heat exchanger 130 may be transferred to the return air for heating or otherwise pre-heating the return air prior to heating the air with the furnace 2000. As may be realized, the heated air may be transferred through the supply plenum 1301 back to the heating space. In one aspect, any suitable filter 1302 may be disposed in or in-line with the return plenum 1300 so that filtered air is provided for contacting the second heat exchanger 130. The modular unit 200A may be located at any suitable location relative to one or more of the modular unit 200B and the furnace 2000. The modular unit 200A, in this aspect, includes the heat recovery chamber 110 and first heat exchanger 116 (which may be in communication with the second heat exchanger through conduit circuit 120) and blower 140. In other aspects the modular unit 200A may include any suitable components of the heat recovery system as described herein. Exhaust gas from the furnace and cooling gas may be provided to the heat recovery chamber 110 through cooling intake 112 and exhaust intake 114 in a manner substantially similar to that described above. In this aspect the blower 140 is provided to pull or draw gas through the heat recovery chamber 110.

Any suitable sensor(s) 1310 may be may be provided for sensing a pressure (or other suitable physical characteristic of the gas within the heat recovery chamber) for determining a pressure within the heat recovery chamber 110. The sensor(s) 1310 may be connected to any suitable controller 1311 (which may include one or more features described above with respect to FIG. 7). In one aspect the controller may be integral to the modular unit 200A while in other aspect the controller may be provided at any suitable location. The sensor(s) 1310 may include a pressure sensor connected to the controller 1311 to form a pressure switch for controlling a pressure within the heat recovery chamber 110. The cooling intake 112 may include any suitable bypass valve 112V for redirecting, limiting or substantially preventing discharge gas from entering the cooling intake 112 for maintaining a predetermined pressure within the heat recovery chamber 110. In one aspect the valve 112V may be connected to the controller 1311 such that when a predetermined pressure within the heat recovery chamber is detected by the sensor(s) 1310 the controller operates the valve 112V to direct at least some of the discharge gas past the cooling intake 112 for maintaining the predetermined pressure or any other suitable pressure. In other aspect the speed of the blower 140 may be adjusted by the controller 1311 for maintaining the predetermined pressure. In other aspects the controller may turn off the blower 140 to maintain the predetermined pressure within the heat recovery chamber. As may be realized a check valve 1410V may be provided in one or more of the heat recovery chamber exhaust 1410, exhaust inlet 114 and cooling intake 112 to substantially prevent a back flow of gas into the heat recovery chamber where a pressure within the heat recovery chamber is lower than atmospheric pressure outside the heat recovery chamber.

In another aspect, still referring to FIG. 13, the sensor(s) 1310 may include a temperature sensor (similar to sensors CS1, CS2 described above) for sensing a temperature of the refrigerant within the first heat exchanger 116. In this aspect any suitable blower or fan 1320 may be provided for circulating air through the return plenum 1300 and the supply plenum 1301. The blower 1320 may be connected to the controller 1311 in any suitable manner. As may be realized, as the furnace 2000 is operating the exhaust from the furnace heats the refrigerant within the first and second heat exchangers 116, 130 and the conduit circuit 120. When the furnace 2000 turns off there may be residual heat stored in the combustion chamber 2000CH of the furnace as well as in the refrigerant. The residual heat from the combustion chamber 2000CH may be drawn from the combustion chamber in any suitable manner, such as by gas flowing through the combustion chamber and into the heat recovery chamber 110 through the exhaust intake. Any suitable blower or fan may be provided for drawing gas from the combustion chamber into the heat recovery chamber when the furnace 2000 is not operating (e.g. turned off). In other aspect the air flow may be provided through convection. In this aspect heated gas from the combustion chamber 2000CH alone or in combination with cooling gas from the cooling intake 112 may continue to be provided to the heat recovery chamber after the furnace 2000 is turned off. This heated gas may continue to heat the refrigerant within the first heat exchanger 116 for transfer to the second heat exchanger where that heat is extracted from the second heat exchanger by the air flowing in the return and supply plenums 1300, 1301 so that heated air is provided to the heating space after the furnace is turned off. The sensor(s) 1310 may send a signal to the controller 1311 when the temperature of, for example, the refrigerant reaches a predetermined temperature. When the predetermined temperature is reached the controller 1311 may turn off the one or more of the blowers 1320, 140 to stop the flow of air into the heating space or adjust a speed of the blowers to decrease the flow of air. In this aspect, any residual heat from the furnace may be extracted which may increase the energy recovered by the system 100, 200. In other aspects, the extraction of residual heat from the furnace may be performed in the manner described above using pressure readings from within the heat recovery chamber. For example, the blowers may be turned off or the speed of the blower may be varied (e.g. decreased) when the pressure within the heat recovery chamber reaches any suitable predetermined pressure. In still other aspects pressure and temperature readings may be used to control the blowers for the recovery of residual heat from the furnace.

In other aspects the sensor(s) 1310 may be configured to detect a pressure of the refrigerant within the first heat exchanger 116 and/or a temperature of the first heat exchanger 116 for determining the presence of frost on the first heat exchanger. For example, a compressor 150 may be provided to at least partly effect the flow of refrigerant through the conduit circuit 120 as described above. The sensor(s) 1310 may be configured to send signals to, for example, controller 1311 indicating a decrease in pressure and/or temperature within the first heat exchanger at which frost may form. The controller may be configured to, based on the sensor signals, turn off the compressor 150 so that the temperature and pressure of the first heat exchanger 116 rise to allow dissipation of the frost. The controller 1311 may be configured to use the sensor data (in e.g. in a closed loop feedback system) for setting compressor 150 on/off times where the compressor on/off times may be adjusted by the controller in predetermined time increments.

Referring now to FIG. 14A, in the aspects of the disclosed embodiment described herein the heat recovery chamber 110, 110A, 110C may have any suitable configuration for mixing the exhaust gas from exhaust intake 114 and the cooling gas from cooling intake 112. In one aspect the heat recovery chamber may have one or more features for mixing the exhaust gas and cooling gas. For example, ends of the cooling intake 112 and exhaust intake 114 within the heat recovery chamber may be angled towards a wall or mixing surface 1105 (e.g. the walls may be contoured or textured) of the heat recovery chamber 110 so that the exhaust gas and cooling gas are reflected by the wall or mixing surface in any suitable manner for mixing or otherwise combining the exhaust gas with the cooling gas. In another aspect the heat recovery chamber 110, 11B may include one or more vanes 1400 configured to direct the exhaust gas and cooling gas in any suitable direction(s) for mixing or otherwise combining the exhaust gas and cooling gas. In yet another aspect the heat recovery chamber 110, 110B may include any suitable diffuser 1402 or other suitable mixing element for mixing or otherwise combining the exhaust gas and cooling gas. In still other aspects, the heat recovery chamber 110, 110B may include one or more of the mixing surface 1105, vanes 1400, diffuser(s) 1402 and/or any other suitable mixing structure for mixing or otherwise combining the exhaust gas and cooling gas provided by the exhaust gas intake 114 and the cooling intake 112.

Referring to FIG. 14B and FIG. 14C the heat recovery chamber 110, 110B may be configured so that the exhaust inlet 114 and cooling intake 112 are disposed on opposing sides or sides of the heat recovery chamber 110, 110B that are angled relative to one another. For example, as can be seen in FIG. 14B the exhaust gas intake 114 and the cooling intake 112 are disposed on opposing sides of the heat recovery chamber 110, 110B so that the intakes substantially face one another. In this aspect the exhaust gas and cooling gas may be opposingly directed towards one another for mixing. As may be realized, the exhaust intake 114 and cooling intake 112 may be vertically or horizontally offset with one another or in-line with one another so that the exhaust gas and cooling gas provided to the heat recovery chamber impinge each other at any predetermined angle. As may also be realized, in one aspect, where the first heat exchanger 116 is located within the heat recovery chamber 110, the first heat exchanger may be disposed between an outlet or exhaust 1410 of the heat recovery chamber and the inlets 114, 112 so that the mixture of exhaust gas and cooling gas passes through the first heat exchanger 116 before entering the outlet or exhaust 1410. In another aspect, where the first heat exchanger 116 is located in a separate heat exchange chamber 110B (e.g. such as described above with respect to FIGS. 11 and 12) the mixture of exhaust gas and cooling gas may exit the heat recovery chamber through outlet or exhaust 1410 for transfer to the heat exchange chamber 110B.

As can be seen in FIGS. 14C and 14D, the exhaust gas intake 114 and cooling intake 112 may be disposed on angled sides of the heat recovery chamber in any suitable manner such as in a manner described with respect to FIG. 14B. As may be realized, where the first heat exchanger 116 is located within the heat recovery chamber 110, the first heat exchanger may be disposed between the outlet or exhaust 1410 of the heat recovery chamber and the inlets 114, 112 so that the mixture of exhaust gas and cooling gas passes through the first heat exchanger 116 before entering the outlet or exhaust 1410. In another aspect, where the first heat exchanger 116 is located in a separate heat exchange chamber 110B (e.g. such as described above with respect to FIGS. 11 and 12) the mixture of exhaust gas and cooling gas may exit the heat recovery chamber through outlet or exhaust 1410 for transfer to the heat exchange chamber 110B.

Referring to FIG. 14E, in accordance with an aspect of the disclosed embodiment the first heat exchanger may have any suitable configuration. In one aspect the first heat exchanger 116 may have a planar configuration while in other aspects the first heat exchanger 116′ (which includes one or more of heat exchange elements 116A′, 116B′ which are substantially similar to heat exchange elements 116A, 116B described above) may have cylindrical configuration. For example, first the heat exchange element 116A′ may substantially divide the heat recovery chamber into a first portion 110P1 and second portion 110P2 (and where provided the heat exchanger 116B further divides the heat recovery chamber into at least a third portion disposed between the second portion and the exhaust 1410). The exhaust gas and cooling gas is introduced into the first portion 110P1 and the mixture of the exhaust gas and cooling gas exits through the second portion 110P2 where the mixed gas passes from the first portion 110P1 through the first heat exchanger 116A to the second portion 110P2, and in one aspect, through the heat exchanger 116B. In this example the first heat exchanger 116A may include coils arranged in a cylindrical arrangement so as to have an interior that forms the second portion 110P2 (and/or the heat exchanger 116B has coils arranged in a cylindrical arrangement to form at least the third portion). The exhaust gas and cooling gas is introduced into the first portion, passes through the coils of the first heat exchanger 116A to the interior and then, in one aspect, through the coils of the heat exchanger 116B and exits the outlet or exhaust 1410. In another aspect, as shown in FIG. 14F, the exhaust gas and cooling gas enters the interior of the first heat exchanger (e.g. into portion 110P2) passes through the coils of the first heat exchanger 116A to the first portion 110P1 where the gas, in one aspect passes through heat exchanger 116B, and exits through the outlet or exhaust 1410. In other aspects the heat exchanger 116B is omitted.

Referring to FIG. 16 the heat recovery system described herein can be employed with a boiler system 1600 to provide heated air to a heating space 1650 within a habitable structure. For example, exhaust gas from boiler 1600 may be provided to heat recovery chamber 110 through exhaust gas inlet 114. Cool dry gas (such as for example, indoor air and/or cooling gas from the heat recovery chamber as described above) is provided to the heat recovery chamber 110 through cooling intake 112. The combined exhaust gas and cooling gas contacts the first heat exchanger 116 (which includes one or more of heat exchange elements 116A, 116B) and at least a portion of the exhaust gas exits outside the habitable structure through exhaust 1410. Heat is transferred from the first heat exchanger 116 to the second heat exchanger 130 (which includes one or more of heat exchange elements 130A, 130B) through conduit 120 (and/or conduit 120A) as described above. The second heat exchanger 130 is disposed within or inline with an air delivery system having a fan or blower 1621, a supply duct 1620 and one or more air registers 1610, 1611 through which heated supply air is introduced to the heating space 1650. In this aspect the second heat exchanger 130 is disposed between the supply duct 1620 and the air registers 1610, 1611 so that air forced through the supply duct by blower 1621 passes through the second heat exchanger 130 so that heat extracted from the second heat exchanger heats the air for delivery into the heating space through the air registers 1610, 1611.

As may be realized, in one aspect, the heat transferred to the second heat exchanger 130 from the first heat exchanger 116 (whether the system is employed with a furnace or boiler) is used to heat any suitable heat sink or heat transfer medium. Referring to FIG. 17 in one aspect water within a hot water tank 1700 is heated with the heat recovery system described herein. For example, an air duct 1710 may be disposed adjacent a water chamber 1700C of the hot water tank 1700. In this aspect the air duct 1710 is coiled around the water chamber 1700C while in other aspects air duct(s) 1710 may be disposed within the water chamber 1700C or have any other suitable spatial arrangement/configuration relative to the water chamber 1700C for heating water within the water chamber 1700 in the manner described herein. In one aspect the second heat exchanger 130 may be disposed so air passing through the air duct 1710 is forced or pulled through the second heat exchanger 130, in any suitable manner (such as by blower 140) before entering the air duct 1710. The second heat exchanger 130 may heat the air so that as the heated air passes through the air duct 1710 heat is transferred from the air to the water within the water chamber 1700C in any suitable manner. The air may be drawn from the space in which the hot water tank 1700 is located or from any other suitable source and exhausted back into the space in which the hot water tank is located or to any other suitable location (such as outside the habitable space). As may be realized the flow rate of the air and/or the length of the air duct 1710 may be such that substantially all of the heat stored in the air is transferred to the water within the water chamber 1700C.

In one aspect the disclosed embodiment is directed to a method of recovering heat and energy from fuel combustion. The method includes feeding excess heat and exhaust gas emitted as a result of fuel combustion into a heat recovery chamber 110 which contains a first heat exchanger 116 (fluid filled) coupled with a fluid containing conduit circuit(s) 120, 120A. Typically, the fluid comprises a refrigerant. The method further includes feeding cooling gas into the heat recovery chamber so that the cooling gas is mixed with the exhaust gas to produce a mixed gas with potential energy. The method may also include effectuating heat energy exchange through the mixed gas and excess heat interacting with the first heat exchanger 116. As a result, the temperature and pressure within the first heat exchanger 116 and fluid containing conduit circuit(s) 120, 120A rises. The method may also include releasing the heat energy by, for example, forced (or any other flow of) air blowing over a second heat exchanger 117 that is in fluid communication with one fluid containing conduit circuit(s) 120, 120A exterior to the heat recovery chamber.

In accordance with one or more aspects of the disclosed embodiment a heat recovery system in a habitat to be heated by a furnace having a controller coupled to a thermostat, the heat recovery system includes a chamber including a cooling intake, an emissions intake and a chamber exhaust, the emissions intake is configured for receiving exhaust gas emitted as a result of fuel combustion in the furnace and the chamber exhaust is configured to discharge emissions from the chamber; a heat recovery exchanger disposed within the chamber for contacting a mixture of cooling gas introduced through the cooling intake and the exhaust gas introduced through the emissions intake such that heat exchange is effected; at least one fluid circuit in communication with the heat recovery exchanger; a heat extraction exchanger in fluid communication with the heat recovery exchanger through the at least one fluid circuit to effect heat exchange between the heat extraction exchanger and an airstream running therethrough; and a temperature sensor located in a supply plenum of the furnace and having a predetermined hi temperature set point and a predetermined low temperature set point; where the controller is configured so that in response to a heat call from the thermostat, the furnace is repeatedly cycled between on and off states when the controller registers temperature sensor signals corresponding to the predetermined hi temperature set point and the predetermined low temperature set point.

In accordance with one or more aspects of the disclosed embodiment the heat recovery system further includes a pressure regulating assembly in communication with the chamber and the chamber exhaust for regulating a pressure in the heat recovery system.

In accordance with one or more aspects of the disclosed embodiment the pressure regulating assembly includes a fan communicably coupled to the chamber exhaust and configured to draw the emissions from the chamber.

In accordance with one or more aspects of the disclosed embodiment the cooling intake is communicably coupled to the chamber exhaust and is configured to extract at least a portion of the emissions for recirculation as the cooling gas.

In accordance with one or more aspects of the disclosed embodiment the heat recovery exchanger and the heat extraction exchanger comprise a multi-stage heat exchange system including at least: a first stage having a primary heat recovery exchanger element and a primary heat extraction exchanger element communicably coupled to each other through a primary fluid circuit of the at least one fluid circuit; and a second stage having a secondary heat recovery exchanger element and a secondary heat extraction exchanger element communicably coupled to each other through a secondary fluid circuit of the at least one fluid circuit.

In accordance with one or more aspects of the disclosed embodiment each stage of the multi-stage heat exchange system is independently operable from another stage of the multi-stage heat exchange system.

In accordance with one or more aspects of the disclosed embodiment the first stage of the multi-stage heat exchange system effects heat exchange during both furnace on and off states.

In accordance with one or more aspects of the disclosed embodiment the second stage of the multi-stage heat exchange system is operative and effects heat exchange during furnace on states and inoperative during furnace off states.

In accordance with one or more aspects of the disclosed embodiment a burner of the furnace is switched on and off corresponding to a furnace on and off cycle and a return air blower of the furnace continues to run during the heat call.

In accordance with one or more aspects of the disclosed embodiment, the heat recovery system is configured to be combined with a heating furnace to effects the coupling of a PVC exhaust duct to the combination of the heat recovery assembly/system 100 and the furnace 2000.

In accordance with one or more aspects of the disclosed embodiment a heat recovery system includes a furnace having a furnace exhaust, a return plenum and a controller coupled to a thermostat; a chamber including a cooling intake, an emissions intake and a chamber exhaust, the emissions intake being communicably coupled to the furnace exhaust so that exhaust gas emitted as a result of fuel combustion in the furnace is transferred to the chamber, the chamber exhaust is configured to discharge emissions from the chamber, and the cooling intake is configured to effect transfer of at least a portion of the emissions from the chamber exhaust to the chamber as cooling gas; a heat recovery exchanger disposed within the chamber for contacting a mixture of the cooling gas and the exhaust gas such that heat exchange is effected; at least one fluid circuit in communication with the heat recovery exchanger; a heat extraction exchanger in fluid communication with the heat recovery exchanger through the at least one fluid circuit and in thermal communication with an airstream running through the return plenum for transferring heat from the heat extraction exchanger to the airstream; and a temperature sensor located in a supply plenum of the furnace and having a predetermined hi temperature set point and a predetermined low temperature set point; where the controller is configured so that in response to a heat call from the thermostat, the furnace is repeatedly cycled between on and off states throughout the heat call when the controller registers temperature sensor signals corresponding to the predetermined hi temperature set point and the predetermined low temperature set point.

In accordance with one or more aspects of the disclosed embodiment the heat recovery system further includes a pressure regulating assembly in communication with the chamber and the chamber exhaust for regulating a pressure in the heat recovery system.

In accordance with one or more aspects of the disclosed embodiment the pressure regulating assembly includes a fan communicably coupled to the chamber exhaust and configured to draw the emissions from the chamber.

In accordance with one or more aspects of the disclosed embodiment the heat recovery exchanger and the heat extraction exchanger comprise a multi-stage heat exchange system including at least: a first stage having a primary heat recovery exchanger element and a primary heat extraction exchanger element communicably coupled to each other through a primary fluid circuit of the at least one fluid circuit; and a second stage having a secondary heat recovery exchanger element and a secondary heat extraction exchanger element communicably coupled to each other through a secondary fluid circuit of the at least one fluid circuit.

In accordance with one or more aspects of the disclosed embodiment each stage of the multi-stage heat exchange system is independently operable from another stage of the multi-stage heat exchange system.

In accordance with one or more aspects of the disclosed embodiment the first stage of the multi-stage heat exchange system effects heat exchange during both furnace on and off states.

In accordance with one or more aspects of the disclosed embodiment the second stage of the multi-stage heat exchange system is operative and effects heat exchange during furnace on states and inoperative during furnace off states.

In accordance with one or more aspects of the disclosed embodiment a burner of the furnace is switched on and off corresponding to a furnace on and off cycle and a return air blower of the furnace continues to run during the heat call.

In accordance with one or more aspects of the disclosed embodiment the chamber exhaust comprises a PVC duct.

In accordance with one or more aspects of the disclosed embodiment a heating furnace includes a furnace exhaust; a return plenum; a controller coupled to a thermostat; and a heat recovery system including a chamber including a cooling intake, an emissions intake and a chamber exhaust, the emissions intake being communicably coupled to the furnace exhaust so that exhaust gas emitted as a result of fuel combustion in the furnace is transferred to the chamber, the chamber exhaust is configured to discharge emissions from the chamber, and the cooling intake is configured to effect transfer of at least a portion of the emissions from the chamber exhaust to the chamber as cooling gas; a heat recovery exchanger disposed within the chamber for contacting a mixture of the cooling gas and the exhaust gas such that heat exchange is effected; at least one fluid circuit in communication with the heat recovery exchanger; a heat extraction exchanger in fluid communication with the heat recovery exchanger through the at least one fluid circuit and in thermal communication with an airstream running through the return plenum for transferring heat from the heat extraction exchanger to the airstream; and a temperature sensor located in a supply plenum of the furnace and having a predetermined hi temperature set point and a predetermined low temperature set point; where the controller is configured so that in response to a heat call from the thermostat, the furnace is repeatedly cycled, for a duration of the heat call, between on and off states when the controller registers temperature sensor signals corresponding to the predetermined hi temperature set point and the predetermined low temperature set point.

In accordance with one or more aspects of the disclosed embodiment the heating furnace further includes a pressure regulating assembly in communication with the chamber and the chamber exhaust for regulating a pressure in the heat recovery system.

In accordance with one or more aspects of the disclosed embodiment the pressure regulating assembly includes a fan communicably coupled to the chamber exhaust and configured to draw the emissions from the chamber.

In accordance with one or more aspects of the disclosed embodiment the heat recovery exchanger and the heat extraction exchanger comprise a multi-stage heat exchange system including at least: a first stage having a primary heat recovery exchanger element and a primary heat extraction exchanger element communicably coupled to each other through a primary fluid circuit of the at least one fluid circuit; and a second stage having a secondary heat recovery exchanger element and a secondary heat extraction exchanger element communicably coupled to each other through a secondary fluid circuit of the at least one fluid circuit.

In accordance with one or more aspects of the disclosed embodiment each stage of the multi-stage heat exchange system is independently operable from another stage of the multi-stage heat exchange system.

In accordance with one or more aspects of the disclosed embodiment the first stage of the multi-stage heat exchange system effects heat exchange during both furnace on and off states.

In accordance with one or more aspects of the disclosed embodiment the second stage of the multi-stage heat exchange system is operative and effects heat exchange during furnace on states and inoperative during furnace off states.

In accordance with one or more aspects of the disclosed embodiment a burner of the furnace is switched on and off corresponding to a furnace on and off cycle and a return air blower of the furnace continues to run during the heat call.

In accordance with one or more aspects of the disclosed embodiment a heat recovery system, in a habitat to be heated by a furnace having a controller coupled to a thermostat, includes a chamber including a cooling intake, an emissions intake and a chamber exhaust, the emissions intake is configured for receiving exhaust gas emitted as a result of fuel combustion in the furnace and the chamber exhaust is configured to discharge emissions from the chamber; a multiple stage heat recovery exchanger disposed within the chamber for contacting a mixture of cooling gas introduced through the cooling intake and the exhaust gas introduced through the emissions intake such that heat exchange is effected, the multiple stage heat recovery exchanger including at least a first stage and a second stage; at least one fluid circuit in communication with the heat recovery exchanger; a multiple stage heat extraction exchanger in fluid communication with the heat recovery exchanger through the at least one fluid circuit to effect heat exchange between the heat extraction exchanger and an airstream running therethrough, the multiple stage heat extraction exchanger having at least a first stage and a second stage; and a temperature sensor located in a supply plenum of the furnace and having a predetermined hi temperature set point and a predetermined low temperature set point; where the controller is configured so that in response to a heat call from the thermostat, one or more of the first and second stages of the multiple stage heat recovery exchanger and the multiple stage heat extraction exchanger are operative during the furnace on state, the first stages of the multiple stage heat recovery exchanger and the multiple stage heat extraction exchanger are operative during the furnace on state, and the second stages of the multiple stage heat recovery exchanger and the multiple stage heat extraction exchanger are inoperative during the furnace off state.

In accordance with one or more aspects of the disclosed embodiment the heat recovery system further includes a pressure regulating assembly in communication with the chamber and the chamber exhaust for regulating a pressure in the heat recovery system.

In accordance with one or more aspects of the disclosed embodiment the pressure regulating assembly includes a fan communicably coupled to the chamber exhaust and configured to draw the emissions from the chamber.

In accordance with one or more aspects of the disclosed embodiment the cooling intake is communicably coupled to the chamber exhaust and is configured to extract at least a portion of the emissions for recirculation as the cooling gas.

In accordance with one or more aspects of the disclosed embodiment the controller is configured so that in response to a heat call from the thermostat the furnace is repeatedly cycled between on and off states when the controller registers temperature sensor signals corresponding to the predetermined hi temperature set point and the predetermined low temperature set point.

In accordance with one or more aspects of the disclosed embodiment the chamber exhaust comprises a PVC duct.

In accordance with one or more aspects of the disclosed embodiment a heat recovery system, in a habitat to be heated by a furnace having a controller coupled to a thermostat, includes a chamber including an emissions intake, a chamber exhaust and a closed loop cooling intake communicably coupling the chamber exhaust and the chamber, the emissions intake is configured for receiving exhaust gas emitted as a result of fuel combustion in the furnace, the chamber exhaust is configured to discharge emissions from the chamber and the cooling intake is configured to recirculate at least a portion of the emissions from the chamber exhaust to the chamber; a heat recovery exchanger disposed within the chamber for contacting a mixture of cooling gas introduced through the cooling intake and the exhaust gas introduced through the emissions intake such that heat exchange is effected; at least one fluid circuit in communication with the heat recovery exchanger; a heat extraction exchanger in fluid communication with the heat recovery exchanger through the at least one fluid circuit to effect heat exchange between the heat extraction exchanger and an airstream running therethrough; and a temperature sensor located in a supply plenum of the furnace and having a predetermined hi temperature set point and a predetermined low temperature set point; where the controller is configured so that in response to a heat call from the thermostat, the furnace is repeatedly cycled between on and off states when the controller registers temperature sensor signals corresponding to the predetermined hi temperature set point and the predetermined low temperature set point.

In accordance with one or more aspects of the disclosed embodiment the heat recovery system further includes a fan communicably coupled to the chamber exhaust and configured to draw the emissions from the chamber.

In accordance with one or more aspects of the disclosed embodiment the heat recovery exchanger and the heat extraction exchanger comprise a multi-stage heat exchange system including at least: a first stage having a primary heat recovery exchanger element and a primary heat extraction exchanger element communicably coupled to each other through a primary fluid circuit of the at least one fluid circuit; and a second stage having a secondary heat recovery exchanger element and a secondary heat extraction exchanger element communicably coupled to each other through a secondary fluid circuit of the at least one fluid circuit.

In accordance with one or more aspects of the disclosed embodiment each stage of the multi-stage heat exchange system is independently operable from another stage of the multi-stage heat exchange system.

In accordance with one or more aspects of the disclosed embodiment the first stage of the multi-stage heat exchange system effects heat exchange during both furnace on and off states.

In accordance with one or more aspects of the disclosed embodiment the second stage of the multi-stage heat exchange system is operative and effects heat exchange during furnace on states and inoperative during furnace off states.

In accordance with one or more aspects of the disclosed embodiment the chamber exhaust comprises a PVC duct.

In accordance with one or more aspects of the disclosed embodiment a method for recovering heat in a habitat heated by a furnace includes providing a chamber including a cooling intake, an emissions intake and a chamber exhaust, where the emissions intake receives exhaust gas emitted as a result of fuel combustion in the furnace and the chamber exhaust discharges emissions from the chamber; providing a heat recovery exchanger disposed within the chamber for contacting a mixture of cooling gas introduced through the cooling intake and the exhaust gas introduced through the emissions intake such that heat exchange is effected; providing a heat extraction exchanger in fluid communication with the heat recovery exchanger through at least one fluid circuit for effecting heat exchange between the heat extraction exchanger and an airstream running therethrough; providing a temperature sensor in a supply plenum of the furnace and having a predetermined hi temperature set point and a predetermined low temperature set point; and repeatedly cycling the furnace, with a controller that, in response to a heat call from a thermostat, repeatedly cycles the furnace between on and off states for a duration of the heat call when the controller registers temperature sensor signals corresponding to the predetermined hi temperature set point and the predetermined low temperature set point.

In accordance with one or more aspects of the disclosed embodiment the method further includes regulating a pressure within the chamber with a fan communicably coupled to the chamber exhaust where the emissions are drawn from the chamber.

In accordance with one or more aspects of the disclosed embodiment the method further includes supplying cooling gas in a closed loop from the chamber exhaust to the cooling intake.

In accordance with one or more aspects of the disclosed embodiment the heat recovery exchanger and the heat extraction exchanger are provided as a multi-stage heat exchange system including at least: a first stage having a primary heat recovery exchanger element and a primary heat extraction exchanger element communicably coupled to each other through a primary fluid circuit of the at least one fluid circuit; and a second stage having a secondary heat recovery exchanger element and a secondary heat extraction exchanger element communicably coupled to each other through a secondary fluid circuit of the at least one fluid circuit.

In accordance with one or more aspects of the disclosed embodiment the method further includes effecting heat exchange during both furnace on and off states with the first stage of the multi-stage heat exchange system.

In accordance with one or more aspects of the disclosed embodiment method further includes effecting heat exchange during furnace on states with the second stage of the multi-stage heat exchange system.

In accordance with one or more aspects of the disclosed embodiment a burner of the furnace is switched on and off corresponding to a furnace on and off cycle and a return air blower of the furnace continues to run during the heat call.

It should be understood that the foregoing description is only illustrative of the aspects of the disclosed embodiment. Various alternatives and modifications can be devised by those skilled in the art without departing from the aspects of the disclosed embodiment. Accordingly, the aspects of the disclosed embodiment are intended to embrace all such alternatives, modifications and variances that fall within the scope of the appended claims. Further, the mere fact that different features are recited in mutually different dependent or independent claims does not indicate that a combination of these features cannot be advantageously used, such a combination remaining within the scope of the aspects of the invention. 

What is claimed is:
 1. A heat recovery system in a habitat to be heated by a furnace having a controller coupled to a thermostat, the heat recovery system comprising: a chamber including a cooling intake, an emissions intake and a chamber exhaust, the emissions intake is configured for receiving exhaust gas emitted as a result of fuel combustion in the furnace and the chamber exhaust is configured to discharge emissions from the chamber; a heat recovery exchanger disposed within the chamber for contacting a mixture of cooling gas introduced through the cooling intake and the exhaust gas introduced through the emissions intake such that heat exchange is effected; at least one fluid circuit in communication with the heat recovery exchanger; a heat extraction exchanger in fluid communication with the heat recovery exchanger through the at least one fluid circuit to effect heat exchange between the heat extraction exchanger and an airstream running therethrough; and a temperature sensor located in a supply plenum of the furnace and having a predetermined hi temperature set point and a predetermined low temperature set point; where the controller is configured so that in response to a heat call from the thermostat, the furnace is repeatedly cycled between on and off states when the controller registers temperature sensor signals corresponding to the predetermined hi temperature set point and the predetermined low temperature set point.
 2. The heat recovery system of claim 1, further comprising a pressure regulating assembly in communication with the chamber and the chamber exhaust for regulating a pressure in the heat recovery system.
 3. The heat recovery system of claim 2, wherein the pressure regulating assembly includes a fan communicably coupled to the chamber exhaust and configured to draw the emissions from the chamber.
 4. The heat recovery system of claim 1, wherein the cooling intake is communicably coupled to the chamber exhaust and is configured to extract at least a portion of the emissions for recirculation as the cooling gas.
 5. The heat recovery system of claim 1, wherein the heat recovery exchanger and the heat extraction exchanger comprise a multi-stage heat exchange system including at least: a first stage having a primary heat recovery exchanger element and a primary heat extraction exchanger element communicably coupled to each other through a primary fluid circuit of the at least one fluid circuit; and a second stage having a secondary heat recovery exchanger element and a secondary heat extraction exchanger element communicably coupled to each other through a secondary fluid circuit of the at least one fluid circuit.
 6. The heat recovery system of claim 5, wherein each stage of the multi-stage heat exchange system is independently operable from another stage of the multi-stage heat exchange system.
 7. The heat recovery system of claim 5, wherein the first stage of the multi-stage heat exchange system effects heat exchange during both furnace on and off states.
 8. The heat recovery system of claim 5, wherein the second stage of the multi-stage heat exchange system is operative and effects heat exchange during furnace on states and inoperative during furnace off states.
 9. The heat recovery system of claim 1, wherein a burner of the furnace is switched on and off corresponding to a furnace on and off cycle and a return air blower of the furnace continues to run during the heat call.
 10. A heat recovery system comprising: a furnace having a furnace exhaust, a return plenum and a controller coupled to a thermostat; a chamber including a cooling intake, an emissions intake and a chamber exhaust, the emissions intake being communicably coupled to the furnace exhaust so that exhaust gas emitted as a result of fuel combustion in the furnace is transferred to the chamber, the chamber exhaust is configured to discharge emissions from the chamber, and the cooling intake is configured to effect transfer of at least a portion of the emissions from the chamber exhaust to the chamber as cooling gas; a heat recovery exchanger disposed within the chamber for contacting a mixture of the cooling gas and the exhaust gas such that heat exchange is effected; at least one fluid circuit in communication with the heat recovery exchanger; a heat extraction exchanger in fluid communication with the heat recovery exchanger through the at least one fluid circuit and in thermal communication with an airstream running through the return plenum for transferring heat from the heat extraction exchanger to the airstream; and a temperature sensor located in a supply plenum of the furnace and having a predetermined hi temperature set point and a predetermined low temperature set point; where the controller is configured so that in response to a heat call from the thermostat, the furnace is repeatedly cycled between on and off states throughout the heat call when the controller registers temperature sensor signals corresponding to the predetermined hi temperature set point and the predetermined low temperature set point.
 11. The heat recovery system of claim 10, further comprising a pressure regulating assembly in communication with the chamber and the chamber exhaust for regulating a pressure in the heat recovery system.
 12. The heat recovery system of claim 11, wherein the pressure regulating assembly includes a fan communicably coupled to the chamber exhaust and configured to draw the emissions from the chamber.
 13. The heat recovery system of claim 10, wherein a burner of the furnace is switched on and off corresponding to a furnace on and off cycle and a return air blower of the furnace continues to run during the heat call.
 14. The heat recovery system of claim 10, wherein the heat recovery exchanger and the heat extraction exchanger comprise a multi-stage heat exchange system including at least: a first stage having a primary heat recovery exchanger element and a primary heat extraction exchanger element communicably coupled to each other through a primary fluid circuit of the at least one fluid circuit; and a second stage having a secondary heat recovery exchanger element and a secondary heat extraction exchanger element communicably coupled to each other through a secondary fluid circuit of the at least one fluid circuit.
 15. The heat recovery system of claim 14, wherein each stage of the multi-stage heat exchange system is independently operable from another stage of the multi-stage heat exchange system.
 16. The heat recovery system of claim 14, wherein the first stage of the multi-stage heat exchange system effects heat exchange during both furnace on and off states.
 17. The heat recovery system of claim 14, wherein the second stage of the multi-stage heat exchange system is operative and effects heat exchange during furnace on states and inoperative during furnace off states.
 18. A heating furnace comprising: a furnace exhaust; a return plenum; a controller coupled to a thermostat; and a heat recovery system including a chamber including a cooling intake, an emissions intake and a chamber exhaust, the emissions intake being communicably coupled to the furnace exhaust so that exhaust gas emitted as a result of fuel combustion in the furnace is transferred to the chamber, the chamber exhaust is configured to discharge emissions from the chamber, and the cooling intake is configured to effect transfer of at least a portion of the emissions from the chamber exhaust to the chamber as cooling gas; a heat recovery exchanger disposed within the chamber for contacting a mixture of the cooling gas and the exhaust gas such that heat exchange is effected; at least one fluid circuit in communication with the heat recovery exchanger; a heat extraction exchanger in fluid communication with the heat recovery exchanger through the at least one fluid circuit and in thermal communication with an airstream running through the return plenum for transferring heat from the heat extraction exchanger to the airstream; and a temperature sensor located in a supply plenum of the furnace and having a predetermined hi temperature set point and a predetermined low temperature set point; where the controller is configured so that in response to a heat call from the thermostat, the furnace is repeatedly cycled, for a duration of the heat call, between on and off states when the controller registers temperature sensor signals corresponding to the predetermined hi temperature set point and the predetermined low temperature set point.
 19. The heating furnace of claim 18, further comprising a pressure regulating assembly in communication with the chamber and the chamber exhaust for regulating a pressure in the heat recovery system.
 20. The heating furnace of claim 19, wherein the pressure regulating assembly includes a fan communicably coupled to the chamber exhaust and configured to draw the emissions from the chamber.
 21. The heating furnace of claim 18, wherein the heat recovery exchanger and the heat extraction exchanger comprise a multi-stage heat exchange system including at least: a first stage having a primary heat recovery exchanger element and a primary heat extraction exchanger element communicably coupled to each other through a primary fluid circuit of the at least one fluid circuit; and a second stage having a secondary heat recovery exchanger element and a secondary heat extraction exchanger element communicably coupled to each other through a secondary fluid circuit of the at least one fluid circuit.
 22. The heating furnace of claim 18, wherein each stage of the multi-stage heat exchange system is independently operable from another stage of the multi-stage heat exchange system.
 23. The heating furnace of claim 18, wherein the first stage of the multi-stage heat exchange system effects heat exchange during both furnace on and off states.
 24. The heating furnace of claim 18, wherein the second stage of the multi-stage heat exchange system is operative and effects heat exchange during furnace on states and inoperative during furnace off states.
 25. The heating furnace of claim 18, wherein a burner of the furnace is switched on and off corresponding to a furnace on and off cycle and a return air blower of the furnace continues to run during the heat call.
 26. A method for recovering heat in a habitat heated by a furnace, the method comprising: providing a chamber including a cooling intake, an emissions intake and a chamber exhaust, where the emissions intake receives exhaust gas emitted as a result of fuel combustion in the furnace and the chamber exhaust discharges emissions from the chamber; providing a heat recovery exchanger disposed within the chamber for contacting a mixture of cooling gas introduced through the cooling intake and the exhaust gas introduced through the emissions intake such that heat exchange is effected; providing a heat extraction exchanger in fluid communication with the heat recovery exchanger through at least one fluid circuit for effecting heat exchange between the heat extraction exchanger and an airstream running therethrough; providing a temperature sensor in a supply plenum of the furnace and having a predetermined hi temperature set point and a predetermined low temperature set point; and repeatedly cycling the furnace, with a controller that, in response to a heat call from a thermostat, repeatedly cycles the furnace between on and off states for a duration of the heat call when the controller registers temperature sensor signals corresponding to the predetermined hi temperature set point and the predetermined low temperature set point.
 27. The method of claim 26, further comprising regulating a pressure within the chamber with a fan communicably coupled to the chamber exhaust where the emissions are drawn from the chamber.
 28. The method of claim 26, further comprising supplying cooling gas in a closed loop from the chamber exhaust to the cooling intake.
 29. The method of claim 26, wherein the heat recovery exchanger and the heat extraction exchanger are provided as a multi-stage heat exchange system including at least: a first stage having a primary heat recovery exchanger element and a primary heat extraction exchanger element communicably coupled to each other through a primary fluid circuit of the at least one fluid circuit; and a second stage having a secondary heat recovery exchanger element and a secondary heat extraction exchanger element communicably coupled to each other through a secondary fluid circuit of the at least one fluid circuit.
 30. The method of claim 29, further comprising effecting heat exchange during both furnace on and off states with the first stage of the multi-stage heat exchange system.
 31. The method of claim 29, further comprising effecting heat exchange during furnace on states with the second stage of the multi-stage heat exchange system.
 32. The method of claim 29, wherein a burner of the furnace is switched on and off corresponding to a furnace on and off cycle and a return air blower of the furnace continues to run during the heat call. 